Patent GB-228831-A (GB)
Title: Shaft setting arrangement, particularly for electric switches and more particularly for electro-mechanical telephone systems
IPC: H01H67/06
Filed: 1923-11-05
Abstract: 228,831. Baron, H., (Aldendorff, F.). Nov. 5, 1923. Automatic exchange systems; selectors.-A switch of the kind in which the wipers first move in long steps under spring-power to the beginning of a wanted group and are then stepped round in the same direction to a particular line in that group, is arranged so that when employed as a numerical switch it responds directly to impulses, the use of an auxiliary marking switch being avoided. The switch comprises a central shaft and a wiper-carrier surrounding the shaft and normally coupled thereto, the operation of a coupling magnet serving to free the carrier, which is then rotated relatively to the shaft through one or more long steps. In the use of the switch as a numerical selector, the impulses are sent into the coupling magnet over a circuit which includes, in one arrangement, a fourth wiper and a short bank contact engaged by the said wiper when at the beginning of a group, and in a second arrangement, a set of interrupter springs which are closed bv projections on the wiper carrier only when the latter is in a position corresponding to the beginning of a group. Thus, in both arrangements, the circuit of the coupling magnet is opened immediately the wipers commence to move, and they come to rest again after making a single long step for each impulse. Switches constructed with the second arrangement, which may, with suitable circuit arrangements, also be employed as callfinders, comprise a movable stop which stops the wipers in their normal position and is controlled to release the wipers by the member which controls the coupling between the wiper-carrier and shaft. Figs. 8 and 9 show detailed circuit arrangements for a system employing switches, in accordance with the first arrangement previously referred to, as group selectors 200 and connectors 300 and also employing a switch of similar construction as a call-finder 100. Other features of the switches described in the present Specification form the subject-matter of a divided Specification 228,824. Construction of switches; first arrangement, Figs. 3 and 4. The switch shaft 1, rotatably mounted upon a ball 7 in the axis of a hollow magnet 4, has secured to it a stepping-wheel 9 which is normally held by a driving pawl 17 abutting against a stop 20. The wiper-carrier 2, secured to which is a spider 10, is mounted loosely upon the shaft 1, and is normally prevented from rotating under the action of a driving spring 13 the other end of which is fixed to the shaft 1, by the armature 14 of a starting electromagnet 15. The shaft 1 and wiper-carrier 2 are normally coupled together by the armature 27 of the magnet 4 which armature is pivoted to the underside of the stepping wheel 9 and, with the magnet 4 de-energized, projects a coupling member 28 between two arms 16<1>, 16<2>, of the spider 10. When a switch is taken into use as a call-finder, the magnets 4, 15 are energized and the wiper-carrier 2 is driven round at a high speed until a fourth wiper 11, which passes over alternate long and short contacts, reaches a long contact 30 which has been marked by the removal of battery. Magnet 4 is thereby de-energized, and the switch is brought to rest with the projection 31 engaging the next leg 16<2> of the spider, and with the wiper 11 resting on the short contact 26. After the switch has thus been stopped at the beginning of a wanted group of lines, impulses are sent through the stepping magnet 18 whereby the shaft 1 and wiper carrier 2 are stepped together on to the wanted line. At the end of a connection, the magnet 15 is de-energized, the magnet 4 energized, and further impulses are sent through magnet 18 to step the shaft and wiper carrier together until the armature 14 engages the next leg 16 of the spider, after which the shaft 1 is stepped alone until the spring 13 is fully re-tensioned when the circuit of the magnet 18 is opened at off-normal contacts which are closed whenever the shaft 1 and wiper-carrier 2 are displaced from their normal angular relation to one another. The switch, when employed as a " no-normal " call-finder is now fully restored, but when employed as a numerical selector, a further restoration of the wipers and shaft to the beginning of the bank is necessary. This is effected by de-energizing the magnet 4 so as to couple the shaft and wipers together, energizing the magnet 15, and then sending further impulses through the stepping magnet 18 the circuit of which is controlled by other offnormal contacts. In order to minimize the frictional pressure upon the ball bearing 7, the pull of the magnet 4 is reduced after it has attracted its armature bv the insertion of a resistance in its circuit. Alternatively, the magnet may be attached to the shaft 1 or to the stepping-wheel 9. Second arrangement, Figs. 11 and 12, employing only two magnets, the starting magnet 15, Fig. 3, being eliminated. The spider member secured to the wiper-carrier is formed with nine narrow slots 611, Fig. 12, and a tenth wider slot 612 with which a, detent 613 engages. In the normal position, the coupling member 631 lifts the detent 613 so that when the switch is started by the energization of the coupling magnet which withdraws the member 631, the detent 613 rides over the outer ring 615. Upon the release of the switch, the coupling magnet is again energized so that the wipers rotate further until detent 613 engages leg 616, after which the stepping wheel 629 rotates alone and the spring is rewound by stepping magnet 618. When the wheel 629 nears its normal position a cam 639, 640 operates switch members 635, 636 to open successively the circuits of the coupling and stepping magnets. The stepping pawl 630 is connected to the armature 671 through an arm 672, the bent end 673 of which is provided with elongated holes so that by adjustment of the screws 674 and of the stop 670, the position of the wipers on the contact bank on which they are resting may be adjusted as desired. When a switch of this second construction is employed as a group selector, the short and long contacts which alternately make and break the circuit of the coupling magnet as described in a later paragraph in connection with Fig. 8 are replaced by contacts 650, 651, Fig. 12, which are alternately closed and opened by projections 652 and recesses 655. Construction of terminal bank. Two terminal bank arrangements, which permit multiple connections to be effected by straight bare wires, are described, the arrangements being identical with those described in a second divisional application 228,825. Circuit arrangements, Figs. 8 and 9; call-finder 100. When subscriber 101, desiring to call subscriber No. 232, removes his receiver, line relay 102 energizes the group relav 109 which removes battery from long contact 126 and completes the starting circuits 110, 130, 112, 113, 114 for the starting magnet 15 and 110, 112, 4, 115, 116, 120, 122, 224 for the coupling magnet 4. The wipers are thus whirled round until wiper 116 reaches the marked contact 126 when magnet 4 de-energizes and the wipers are brought to rest with wiper 116 engaging contact 128. At the first movement of the wiper-carrier relative to the shaft, off-normal contacts 131 were closed and a relay 234 operated to open contact 224 so that relay 129 now energizes in series with magnet 4. which is no longer energized, and completes the circuit 140, 137, 141 for stepping magnet 18. When the calling line is reached, the test relay 145, energizing over wiper 117 in series with the cut-off relay 104, opens the stepping circuit and extends the connection to the line relay 255 of the group selector 200, which energizes and operates the release relay 258. Relay 160 now energizes and completes a circuit for the upper winding of a relay 167 which connects up magnet 171 in series with interrupter 170 whereby the finder-allotter TF is stepped forward in search of the next idle finder. Group selector 200. The release relay 258 energizes the starting magnet 215 and the first hundreds impulse is repeated over the circuit 260, 268, 257, 270, 275 to the coupling magnet 204 which thus releases the wipers. As soon as wiper 275 leaves contact 276, magnet 204 is de-energized but the wipers will move a full long step in the manner already described before the coupling again becomes effective. Wiper 275 thus comes to rest on contact 277. The second hundreds impulse in a similar manner moves the wipers a further long step into position at the beginning of the second numerical group. The relapse of the change-over relay 266 at the end of the digit energizes relay 282 which completes an interrupter circuit 288, 281, 283, 289 for the stepping magnet 218. When an idle trunk 301, Fig. 9, is reached, test relay 291 operates over the circuit 284, 290, 274, 302, 305 and completes a holding circuit for line relay 255 in series with relay 234 which energizes in series with the calling line and completes circuit 309, 307, 310 for release relay 358. Premature release. If the calling subscriber abandons the call at this stage, the release of relay 355 energizes the change-over relay 316 which completes circuits 309, 312, 319, 318<1>, 321, 375 and 309, 312, 302 for the connector coupling and starting magnets 304, 315, respectively. The wipers 372 - - 375 are thus driven from their normal position. Upon the subsequent release of relay 358, magnets 304, 315 are de-energized, whilst relay 315<1> energizing over contacts 365, 321, 309 closes a fresh circuit 325, 314, 327 for magnet 304 and a circuit 324, 323 for stepping magnet 318. The inner shaft is thus stepped round relatively to the wiper carrier until the normal relative position is reached, in which the spring is fully retensioned and the contacts 365 opened. After the first energization of magnet 304, relay 326 inserts a resistance 328 into its circuit. The opening of contacts 365 de-energizes rela